[GHC] #13173: Investigate old comment at the top of SrcLoc

[GHC]

#13173: Investigate old comment at the top of SrcLoc
-------------------------------------+-------------------------------------
        Reporter:  mpickering        |                Owner:  supersven
            Type:  task              |               Status:  closed
        Priority:  lowest            |            Milestone:  8.4.1
       Component:  Compiler          |              Version:  8.0.1
      Resolution:  fixed             |             Keywords:  newcomer
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  D3763
       Wiki Page:                    |
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Changes (by bgamari):

 * status:  patch => closed
 * resolution:   => fixed
 * milestone:   => 8.4.1


Old description:

> There is a comment at the top of `SrcLoc` which says
>
> {{{
> {-# OPTIONS_GHC -fno-omit-interface-pragmas #-}
>   -- Workaround for Trac #5252 crashes the bootstrap compiler without -O
>   -- When the earliest compiler we want to boostrap with is
>   -- GHC 7.2, we can make RealSrcLoc properly abstract
> }}}
>
> This is a well-defined small task so I will mark it for newcomers.
>
> 1. Try to work out what the pragma is meant to do by reading #5252
> 2. Work out whether we can now make `RealSrcLoc` "properly abstract" (if
> it is not already)
> 3. Remove or update this comment and pragma.
> 4. Pray it doesn't break the whole compiler.

New description:

 There is a comment at the top of `SrcLoc` which says

 {{{#!hs
 {-# OPTIONS_GHC -fno-omit-interface-pragmas #-}
   -- Workaround for Trac #5252 crashes the bootstrap compiler without -O
   -- When the earliest compiler we want to boostrap with is
   -- GHC 7.2, we can make RealSrcLoc properly abstract
 }}}

 This is a well-defined small task so I will mark it for newcomers.

 1. Try to work out what the pragma is meant to do by reading #5252
 2. Work out whether we can now make `RealSrcLoc` "properly abstract" (if
 it is not already)
 3. Remove or update this comment and pragma.
 4. Pray it doesn't break the whole compiler.

--

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13173#comment:7>
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